Connection structure between a tab film and a liquid crystal panel

Abstract

The improved liquid-crystal display device has a slit formed in part of the TAB area where the electrodes on the liquid-crystal display panel are connected to the output terminals on the TAB and the liquid-crystal display panel is bonded to the TAB by means of a first anisotropic conductive adhesive having a comparatively weak adhesive force, such as a thermoplastic anisotropic conductive adhesive, whereas a second anisotropic conductive adhesive having a comparatively strong adhesive force, such as a uv curable adhesive, is coated in the slit. This liquid-crystal display device can be produced by a process that proceeds basically as follows: the electrodes on the liquid-crystal display panel are connected to the output terminals on the TAB by means of a thermoplastic adhesive as the first anisotropic conductive adhesive having a comparatively weak adhesive force; then, the assembly is subjected to an operating test; if the TAB is found to be defective in the operating test, it is replaced and, if no defect is found, a uv curable or a thermosetting adhesive as the second anisotropic conductive adhesive having a comparatively strong adhesive force is coated in the slit and then cured as the output terminals are compressed against the electrodes.

What is claimed is: 
     
       1. A liquid-crystal display device comprising a liquid-crystal display panel having a plurality of electrodes arranged thereon as they are partly exposed at an end of said panel and a flexible film having an IC mounted thereon for driving at least one of said electrodes, said flexible film having at least one lead wire formed thereon serving as an output terminal for said IC, a slit being formed in a region of said flexible film which corresponds to an area of connection where said lead wire is to be connected to one of said electrodes, so that part of said lead wire is exposed in said slit, one of said electrodes and said lead wire being connected by a first adhesive of an anisotropic conductive type except in the area corresponding to said slit, said first adhesive of an anisotropic conductive type having such a weak adhesive force that one of said electrodes as connected to said lead wire can be separated without being damaged, the part of said lead wire which is exposed in said slit being connected to one of said electrodes by a second adhesive of either an insulating type or an anisotropic conductive type that has a greater adhesive force than said first adhesive of an anisotropic conductive type. 
     
     
       2. A liquid-crystal display device comprising a liquid-crystal display panel having a plurality of electrodes arranged thereon as they are partly exposed at an end of said panel and a flexible film having an IC mounted thereon that is connected to said electrodes for driving them, said flexible film having a plurality of lead wires formed thereon serving as output terminals for said IC, a slit being formed in a region of said flexible film which corresponds to an area of connection where said lead wires are to be connected to the respective electrodes, so that part of said lead wires are exposed in said slit, said electrodes and said lead wires being connected by a first adhesive of an anisotropic conductive type in the area of connection excepting the area corresponding to said slit, and the part of said lead wires which is exposed in said slit being connected to said electrodes by a second adhesive of either an insulating type or an anisotropic conductive type that has a greater adhesive force that said first adhesive of an anisotropic conductive type. 
     
     
       3. A liquid-crystal display device according to claim 2, wherein said IC mounting flexible film is a TAB and said first adhesive has such a weak adhesive force that any of the connected electrodes and terminals can be separated without being damaged. 
     
     
       4. A liquid-crystal display device according to claim 2, wherein said slit has a width that is selected in relation to the adhesive force of said first adhesive of an anisotropic conductive type in such a way that said electrodes and said lead wires, after being connected by said first adhesive of an anisotropic conductive type in said area of connection excepting the area corresponding to said slit, can be separated without being damaged. 
     
     
       5. A liquid-crystal display device according to claim 4, wherein the region where said electrodes are connected to said lead wires by the first adhesive of an anisotropic conductive type is divided into two parts. 
     
     
       6. A liquid-crystal display device according to claim 5, wherein said first adhesive of an anisotropic conductive type is thermoplastic whereas said second adhesive is of an anisotropic conductive type that is made of a uv curable resin. 
     
     
       7. In a liquid-crystal display device comprising a liquid-crystal display panel having a plurality of electrodes arranged in an end portion of the panel and a circuit board made of a flexible resin that has a liquid-crystal drive IC mounted thereon, a plurality of output terminals being provided on the surface of said circuit board and connected respectively to said electrodes, the improvement wherein a through slit is formed in said circuit board to expose at least part of said output terminals in the area where said circuit board is to be connected to said liquid-crystal display panel, said liquid-crystal display panel being connected to said circuit board by means of a thermoplastic anisotropic conductive first adhesive between said electrodes and said output terminals and by either a uv curable or a thermosetting second adhesive that is coated in said slit and separate from said first adhesive. 
     
     
       8. A liquid-crystal display device, comprising: a liquid-crystal display panel having a plurality of electrodes arranged thereon and partly exposed at at least one end of said panel;   a wire supporting substrate having a plurality of lead wires formed thereon and aligned respectively with said electrodes;   said lead wires being between said wire supporting substrate and said electrodes, and a through slit being formed in said wire supporting substrate to expose at least part of said lead wires;   a first electrically conductive adhesive contactingly between said electrodes and said lead wires providing electrical conduction between respective aligned lead wires and electrodes without providing electrical conduction between electrodes and between lead wires; and   a second adhesive separate from said first adhesive being within said slit, being contactingly between said part of said lead wires and aligned parts of said electrodes, and contacting said first adhesive.   
     
     
       9. The device of claim 8, wherein said wire supporting substrate is a flexible film. 
     
     
       10. The device of claim 8, wherein said second adhesive has a greater adhesive force than said first adhesive. 
     
     
       11. The device of claim 8, wherein said second adhesive is a thermosetting adhesive and said first adhesive is a thermoplastic adhesive. 
     
     
       12. The device of claim 8, wherein said first adhesive is a conductive adhesive and said second adhesive is a conductive adhesive. 
     
     
       13. The device of claim 8, wherein said slit is surrounded by said wire supporting substrate. 
     
     
       14. The device of claim 8, wherein for each pair of aligned lead wires and electrodes, said first adhesive is provided therebetween at portions spaced on opposite sides of said slit and said second adhesive joins said portions. 
     
     
       15. The device of claim 8, wherein said first adhesive is electrically conductive and said second adhesive is an insulating adhesive. 
     
     
       16. The device of claim 13, wherein for each pair of aligned lead wires and electrodes, said first adhesive is provided therebetween at portions spaced on opposite sides of said slit and said second adhesive joins said portions. 
     
     
       17. The device of claim 16, wherein said wire supporting substrate is a flexible film. 
     
     
       18. The device of claim 13, wherein said wire supporting substrate is a flexible film. 
     
     
       19. The device of claim 10, wherein said slit is surrounded by said wire supporting substrate. 
     
     
       20. The device of claim 19, wherein for each pair of aligned lead wires and electrodes, said first adhesive is provided therebetween at portions spaced on opposite sides of said slit and said second adhesive joins said portions. 
     
     
       21. The device of claim 10, wherein for each pair of aligned lead wires and electrodes, said first adhesive is provided therebetween at portions spaced on opposite sides of said slit and said second adhesive joins said portions. 
     
     
       22. The device of claim 17, wherein said second adhesive has a greater adhesive force than said first adhesive. 
     
     
       23. An electronic display device, comprising: a display substrate having a plurality of electrodes arranged thereon and partly exposed at at least one end of said substrate;   a wire supporting substrate having a plurality of lead wires formed thereon and aligned respectively with said electrodes;   said lead wires being between said wire supporting substrate and said electrodes, and a through slit being formed in said wire supporting substrate to expose at least part of said lead wires;   a first electrically conductive adhesive contactingly between said electrodes and said lead wires providing electrical conduction between respective aligned lead wires and electrodes without providing electrical conduction between electrodes and between lead wires; and   a second adhesive separate from said first adhesive being within said slit, being contactingly between said part of said lead wires and aligned parts of said electrodes, and contacting said first adhesive.   
     
     
       24. The device of claim 23, wherein said second adhesive has a greater adhesive force than said first adhesive. 
     
     
       25. The device of claim 24, wherein said wire supporting substrate is a flexible film. 
     
     
       26. The device of claim 25, wherein said slit is surrounded by said wire supporting substrate; and for each pair of aligned lead wires and electrodes, said first adhesive is provided therebetween at portions spaced on opposite sides of said slit and said second adhesive joins said portions.   
     
     
       27. The device of claim 23, wherein said wire supporting substrate is a flexible film. 
     
     
       28. The device of claim 23, wherein said slit is surrounded by said wire supporting substrate. 
     
     
       29. The device of claim 28, wherein for each pair of aligned lead wires and electrodes, said first adhesive is provided therebetween at portions spaced on opposite sides of said slit and said second adhesive joins said portions.